Reconfigurable microwave antennas are of interest in many applications, providing multi-band, secure, and/or anti-jam communications capability. The primary benefit of such antennas is that multifunctional operation is included in a single design, therefore providing the potential for reduced system size, weight, and cost. Fundamentally, the reconfiguration can be achieved by physical and/or electrical modifications made to the antenna, or by using an impedance matching network that is connected to the antenna. The parameters that may be altered include the operating frequency, radiation pattern, polarization, and beam direction. For example, tuning the resonant frequency of antennas has been demonstrated using diodes, micro-electro-mechanical systems (MEMS), and tunable materials.
In addition to increasing antenna complexity, these techniques may restrict the operational bandwidth and degrade the overall communication performance of the antenna because of the added loss and potential non-linearity induced upon the radio frequency (RF) signal. Some innovative approaches have been proposed to create mechanically reconfigurable antennas in order to lower cost and improve the tunability range. Unfortunately, these approaches generally suffer from the slow speed of the mechanical actuators and their high power consumption.
In view of the above discussion, it can be appreciated that it would be desirable to have improved mechanically reconfigurable antennas.